Surface-modified inorganic nitride, composition, thermally conductive material, and device with thermally conductive layer

ABSTRACT

An object of the present invention is to provide a surface-modified inorganic nitride having excellent dispersibility. Furthermore, another object of the present invention is to provide a composition, a thermally conductive material, and a device with a thermally conductive layer which contain the surface-modified inorganic nitride. 
     The surface-modified inorganic nitride of the present invention includes an inorganic nitride, and a compound which is represented by General Formula (I) and is adsorbed onto a surface of the inorganic nitride.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of PCT International Application No. PCT/JP2018/026599 filed on Jul. 13, 2018, which claims priority under 35 U.S.C. § 119(a) to Japanese Patent Application No. 2017-138356 filed on Jul. 14, 2017. The above application is hereby expressly incorporated by reference, in its entirety, into the present application.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a surface-modified inorganic nitride, a composition, a thermally conductive material, and a device with a thermally conductive layer.

2. Description of the Related Art

In order to widen the range of applications of an inorganic nitride, a method of modifying the surface of the inorganic nitride has been suggested.

For example, in Example of JP2011-236376A, a method of treating the surface of aluminum nitride with 4-biphenylcarboxylic acid, 4-biphenylmethanol, or the like is disclosed.

SUMMARY OF THE INVENTION

In a case where an inorganic nitride is used by being mixed with an organic substance such as a resin binder, the inorganic nitride is required to exhibit further improved affinity with the organic substance. For example, in a case where an inorganic nitride such as boron nitride is used as a thermally conductive material by being mixed with an organic substance, in view of further improving the thermally conductive properties, the improvement of the dispersibility of the inorganic nitride in the organic substance is desired. In order to improve the dispersibility of the inorganic nitride, the surface of the inorganic nitride needs to be modified.

The present inventors prepared a surface-modified inorganic nitride obtained by treating a surface of boron nitride with 4-biphenylcarboxylic acid or 4-biphenylmethanol with reference to JP2011-236376A, mixed the surface-modified inorganic nitride with an organic substance to prepare a thermally conductive material, and evaluated the dispersibility of the surface-modified inorganic nitride in the organic substance, and as a result, the present inventors found that the dispersibility was insufficient and was required to be further improved.

Therefore, an object of the present invention is to provide a surface-modified inorganic nitride having excellent dispersibility.

Furthermore, another object of the present invention is to provide a composition, a thermally conductive material, and a device with a thermally conductive layer which contain the surface-modified inorganic nitride.

As a result of thorough examination conducted to achieve the objects, the present inventors have found that the objects can be achieved by using an inorganic nitride subjected to a surface treatment with a compound represented by General Formula (I), and have completed the present invention.

That is, the present inventors have found that the objects can be achieved by the following constitution.

[1] A surface-modified inorganic nitride comprising:

an inorganic nitride; and

a compound which is represented by General Formula (I) and is adsorbed onto a surface of the inorganic nitride.

[2] The surface-modified inorganic nitride described in [1],

in which X is a hydroxyl group, a carboxylic acid group, a phosphonic acid group, a phosphoric acid group, a phosphinic acid group, a sulfonic acid group, or a thiol group.

[3] The surface-modified inorganic nitride described in [1] or [2],

in which Y is an aromatic hydrocarbon ring group.

[4] The surface-modified inorganic nitride described in [3],

in which Y is a polycyclic aromatic hydrocarbon ring group containing three or more benzene rings.

[5] The surface-modified inorganic nitride described in [4],

in which Y is a pyrene ring group.

[6] The surface-modified inorganic nitride described in any one of [1] to [5],

in which the inorganic nitride is at least one kind of nitride selected from the group consisting of boron nitride and aluminum nitride.

[7] The surface-modified inorganic nitride described in [6],

in which the inorganic nitride is boron nitride.

[8] A composition comprising:

the surface-modified inorganic nitride described in any one of [1] to [7]; and

a polymerizable monomer.

[9] The composition described in [8],

in which the polymerizable monomer has a group selected from the group consisting of an acryloyl group, a methacryloyl group, an oxiranyl group, an oxetanyl group, and a vinyl group.

[10] The composition described in [8] or [9],

in which the polymerizable monomer or a cured substance thereof exhibits liquid crystallinity.

[11] The composition described in any one of [8] to [10] that is used for forming a thermally conductive material.

[12] A thermally conductive material comprising the surface-modified inorganic nitride described in any one of [1] to [7].

[13] The thermally conductive material described in [12] that is in the form of a sheet.

[14] The thermally conductive material described in [12] or [13] that is used in a heat dissipation sheet.

[15] A device with a thermally conductive layer, comprising:

a device; and

a thermally conductive layer which is disposed on the device and contains the thermally conductive material described in any one of [12] to [14].

According to the present invention, it is possible to provide a surface-modified inorganic nitride having excellent dispersibility.

Furthermore, according to the present invention, it is possible to provide a composition, a thermally conductive material, and a device with a thermally conductive layer which contain the surface-modified inorganic nitride.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows ultraviolet⋅visible absorption spectra of a compound C-2-containing solution before and after the addition of boron nitride.

FIG. 2 shows ultraviolet⋅visible absorption spectra of a compound C-3-containing solution before and after the addition of boron nitride.

FIG. 3 shows ultraviolet⋅visible absorption spectra of a compound C-8-containing solution before and after the addition of boron nitride.

FIG. 4 shows ultraviolet⋅visible absorption spectra of a compound C-15-containing solution before and after the addition of boron nitride.

FIG. 5 shows ultraviolet⋅visible absorption spectra of a compound C-28-containing solution before and after the addition of boron nitride.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a surface-modified inorganic nitride, a composition, a thermally conductive material, and a device with a thermally conductive layer according to an embodiment of the present invention will be specifically described.

The following constituent elements may be described based on the representative embodiments of the present invention, but the present invention is not limited to the embodiments.

In the present specification, the numerical range expressed using “to” means a range including the numerical values listed before and after “to” as a lower limit and an upper limit.

In the present specification, the description of “(meth)acryloyl group” means “either or both of an acryloyl group and a methacryloyl group”.

In the present specification, an oxiranyl group is a functional group which is also referred to as an epoxy group. For example, a group, in which two adjacent carbon atoms of a saturated hydrocarbon ring group are bonded to each other through an oxo group (—O—) such that an oxirane ring is formed, and the like are also included in the oxiranyl group.

In the present specification, the acid anhydride group may be a substituent obtained by removing any hydrogen atom from an acid anhydride such as maleic acid anhydride, phthalic acid anhydride, pyromellitic acid anhydride, or trimellitic acid anhydride.

In the present specification, a “surface-modified inorganic nitride” means an inorganic nitride whose surface is modified with a compound (hereinafter, also referred to as a “specific compound”) represented by General Formula (I) which will be described later.

In the present specification, “surface-modified” means a state where a specific compound which will be described later is adsorbed onto at least a portion of the surface of an inorganic nitride. The way the specific compound is adsorbed is not particularly limited, but it is preferable that the specific compound is in a bonded state. “Surface-modified” also includes a state where an organic group (for example, a cationic group) obtained by desorption of a portion of a specific compound forms a bond with a surface of an inorganic nitride. The bond may be any one of a covalent bond, a coordinate bond, an ionic bond, a hydrogen bond, a van der Waals bond, or a metallic bond. In the “surface-modified” state, a monolayer may be formed on at least a portion of the surface of the inorganic nitride.

In the present specification, only a portion of the surface of the inorganic nitride may be modified, or the entire surface of the inorganic nitride may be modified.

In the present specification, in a case where the description of “may have a substituent” appears, the type of a substituent, the position of a substituent, and the number of substituents are not particularly limited. The number of substituents may be, for example, 1, 2, 3, or more. Examples of the substituent include a group of monovalent nonmetallic atoms excluding a hydrogen atom, and the substituent can be selected from the following substituent group T, for example.

Substituent group T: a halogen atom (—F, —Br, —Cl, or —I), a hydroxyl group, an alkoxy group, an aryloxy group, a thiol group, an alkylthio group, an arylthio group, an alkyldithio group, an aryldithio group, an amino group, a N-alkylamino group, a N,N-dialkylamino group, a N-arylamino group, a N,N-diarylamino group, a N-alkyl-N-arylamino group, an acyloxy group, a carbamoyloxy group, a N-alkylcarbamoyloxy group, a N-arylcarbamoyloxy group, a N,N-dialkylcarbamoyloxy group, a N,N-diarylcarbamoyloxy group, a N-alkyl-N-arylcarbamoyloxy group, an alkylsulfoxy group, an arylsulfoxy group, an acylthio group, an acylamino group, a N-alkylacylamino group, a N-arylacylamino group, a ureide group, a N′-alkylureide group, a N′,N′-dialkylureide group, a N′-arylureide group, a N′,N′-diarylureide group, a N′-alkyl-N′-arylureide group, a N-alkylureide group, a N-arylureide group, a N′-alkyl-N-alkylureide group, a N′-alkyl-N-arylureide group, a N′,N′-dialkyl-N-alkylureide group, a N′,N′-dialkyl-N-arylureide group, a N′-aryl-N-alkylureide group, a N′-aryl-N-arylureide group, a N′,N′-diaryl-N-alkylureide group, a N′,N′-diaryl-N-arylureide group, a N′-alkyl-N′-aryl-N-alkylureide group, a N′-alkyl-N′-aryl-N-arylureide group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a N-alkyl-N-alkoxycarbonylamino group, a N-alkyl-N-aryloxycarbonylamino group, a N-aryl-N-alkoxycarbonylamino group, a N-aryl-N-aryloxycarbonylamino group, a formyl group, an acyl group, a carboxy group and a conjugated base group thereof, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a N-alkylcarbamoyl group, a N,N-dialkylcarbamoyl group, a N-arylcarbamoyl group, a N,N-diarylcarbamoyl group, a N-alkyl-N-arylcarbamoyl group, an alkylsufinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a sulfo group (—SO₃H) and a conjugated base group thereof, an alkoxysulfonyl group, an aryloxysulfonyl group, a sulfinamoyl group, a N-alkylsulfinamoyl group, a N,N-dialkylsulfinamoyl group, a N-arylsulfinamoyl group, a N,N-diarylsulfinamoyl group, a N-alkyl-N-arylsulfinamoyl group, a sulfamoyl group, a N-alkylsulfamoyl group, a N,N-dialkylsulfamoyl group, a N-arylsulfamoyl group, a N,N-diarylsulfamoyl group, a N-alkyl-N-arylsulfamoyl group, a N-acylsulfamoyl group and a conjugated base group thereof, a N-alkylsulfonylsulfamoyl group (—SO₂NHSO₂(alkyl)) and a conjugated base group thereof, a N-arylsulfonylsulfamoyl group (—SO₂NHSO₂(aryl)) and a conjugated base group thereof, a N-alkylsulfonylcarbamoyl group (—CONHSO₂(alkyl)) and a conjugated base group thereof, a N-arylsulfonylcarbamoyl group (—CONHSO₂(aryl)) and a conjugated base group thereof, an alkoxysilyl group (—Si(Oalkyl)₃), an aryloxysilyl group (—Si(Oaryl)₃), a hydroxysilyl group (—Si(OH)₃) and a conjugated base group thereof, a phosphono group (—PO₃H₂) and a conjugated base group thereof, a dialkylphosphono group (—PO₃(alkyl)₂), a diarylphosphono group (—PO₃(aryl)₂), an alkylarylphosphono group (—PO₃(alkyl)(aryl)), a monoalkylphosphono group (—PO₃H(alkyl)) and a conjugated base group thereof, a monoarylphosphono group (—PO₃H(aryl)) and a conjugated base group thereof, a phosphonooxy group (—OPO₃H₂) and a conjugated base group thereof, a dialkylphosphonooxy group (—OPO₃(alkyl)₂), a diarylphosphonooxy group (—OPO₃(aryl)₂), an alkylarylphosphonooxy group (—OPO₃(alkyl)(aryl)), a monoalkylphosphonooxy group (—OPO₃H(alkyl)) and a conjugated base group thereof, a monoarylphosphonooxy group (—OPO₃H(aryl)) and a conjugated base group thereof, a cyano group, a nitro group, an aryl group, an alkyl group, a heterocyclic group, an oxiranyl group, an alkenyl group, and an alkynyl group.

These substituents may form a ring by being bonded to each other, if possible, or by being bonded to a group substituted with the substituent.

[Surface-Modified Inorganic Nitride]

The surface-modified inorganic nitride according to the embodiment of the present invention includes an inorganic nitride, and a compound (specific compound) which is represented by General Formula (I) described later and is adsorbed onto a surface of the inorganic nitride. In other words, the surface-modified inorganic nitride according to the embodiment of the present invention is a surface-modified inorganic nitride obtained by modifying a surface of an inorganic nitride with a specific compound which will be described later.

In the surface-modified inorganic nitride according to the embodiment of the present invention, a compound (specific compound) represented by General Formula (I) which will be described later is used as a surface modifier for the inorganic nitride.

As the characteristic point of the specific compound, Y which is an aromatic hydrocarbon ring group or an aromatic heterocyclic group has one or more group (a group represented by *-L¹-X in General Formula (I)) having X which is a hydrogen-bonding group and one or more groups (a group represented by *-L²-Z in General Formula (I)) having Z which is an adsorptive group, as a substituent.

In a case of the specific compound, by the presence of the hydrogen-bonding group, a plurality of specific compounds are easily linked to each other due to hydrogen-bonding interaction. As a result, it is considered that the specific compounds are linked to each other to form a planar structure having a plurality of aromatic hydrocarbon ring groups or a plurality of aromatic heterocyclic groups (corresponding to Y) and are easily adsorbed onto a surface of the inorganic nitride. Moreover, it is confirmed that particularly in a case where the inorganic nitride is boron nitride, adsorptivity is further improved.

A surface-modified inorganic nitride formed by modifying the surface of the inorganic nitride with the specific compound according to the above mechanism has excellent dispersibility. As a result, it is estimated that surface-modified inorganic nitrides are present in a well-dispersed state without being unevenly distributed in a material containing the surface-modified inorganic nitrides, and thus the thermally conductive properties of the material are excellent. In particular, it is considered that in a case where the specific compound has a polymerizable group, in a cured substance obtained from a composition containing the surface-modified inorganic nitride and the polymerizable monomer, a conductive path between the surface-modified inorganic nitrides is easily formed through the polymerizable monomer, and thus the thermally conductive properties are further improved.

Furthermore, in a case where the specific compound has a fused-ring structure in a molecule, the obtained surface-modified inorganic nitride is considered to also have a function of aligning a polymerizable monomer. As a result, in particular, in a case where the polymerizable monomer or a cured substance thereof exhibits liquid crystallinity, the polymerizable monomers or cured substances thereof are aligned (vertical alignment) on the surface of the surface-modified inorganic nitride, and the aligned liquid crystal components are interposed between the surface-modified inorganic nitrides. Accordingly, the thermally conductive properties between the surface-modified inorganic nitrides are further improved, and as a result, it is estimated that the overall thermally conductive properties of the material are further improved.

Hereinafter, the components contained in the surface-modified inorganic nitride will be specifically described, and then a method for producing the surface-modified inorganic nitride, the use of the surface-modified inorganic nitride, and the like will be specifically described.

<Inorganic Nitride>

The type of the inorganic nitride is not particularly limited.

Examples of the inorganic nitride include boron nitride (BN), carbon nitride (C₃N₄), silicon nitride (Si₃N₄), gallium nitride (GaN), indium nitride (InN), aluminum nitride (AlN), chromium nitride (Cr₂N), copper nitride (Cu₃N), iron nitride (Fe₄N or Fe₃N), lanthanum nitride (LaN), lithium nitride (Li₃N), magnesium nitride (Mg₃N₂), molybdenum nitride (Mo₂N), niobium nitride (NbN), tantalum nitride (TaN), titanium nitride (TiN), tungsten nitride (W₂N, WN₂, or WN), yttrium nitride (YN), zirconium nitride (ZrN), and the like.

The above inorganic nitrides may be used singly, or a plurality thereof may be used in combination.

In view of further improving the thermally conductive properties of the obtained surface-modified inorganic nitride, it is preferable that the inorganic nitride contains at least one kind of atom selected from the group consisting of a boron atom, an aluminum atom, and a silicon atom. More specifically, the inorganic nitride is more preferably at least one kind of nitride selected from the group consisting of boron nitride, aluminum nitride, and silicon nitride, even more preferably at least one kind of nitride selected from the group consisting of boron nitride and aluminum nitride, and particularly preferably boron nitride.

The shape of the inorganic nitride is not particularly limited, and the inorganic nitride may have a granule shape, a film shape, or a plate shape. In a case where the inorganic nitride has a granule shape, for example, the inorganic nitride may have a rice grain shape, a spherical shape, a cubical shape, a spindle shape, a scale shape, an aggregated shape, or an amorphous shape.

The size of the inorganic nitride is not particularly limited. However, in view of further improving the dispersibility of the surface-modified inorganic nitride, an average particle diameter of the inorganic nitrides is preferably 500 μm or less, more preferably 300 μm or less, and even more preferably 200 μm or less. The lower limit of the size is not particularly limited. However, in view of handleability, the lower limit is preferably 10 nm or greater, and more preferably 100 nm or greater.

As a method for measuring the average particle diameter, 100 inorganic nitrides are randomly selected using an electron microscope, particle diameters (major axes) of the inorganic nitrides are measured, and the arithmetic mean thereof is calculated. In a case where a commercial product is used, the value listed in the catalog may be used.

<Compound represented by General Formula (I)>

The compound (specific compound) represented by General Formula (I) is a component adsorbed onto the surface of the inorganic nitride, as described above. Hereinafter, the specific compound will be described.

In General Formula (I), m and n each independently represent an integer of 1 or greater. The upper limit of each of m and n is not particularly limited, but is 10 or smaller, for example.

In General Formula (I), X represents a hydroxyl group (—OH), a carboxylic acid group (—COOH), a phosphonic acid group (—PO(OH)₂), a phosphoric acid group (—OP(═O)(OH)₂), a phosphinic acid group (—HPO(OH)), a sulfonic acid group (—SO₃H), a thiol group (—SH), or an amino group.

The amino group is not particularly limited, and may be any of a primary amino group, a secondary amino group, or a tertiary amino group. Specific examples thereof include an amino group represented by —N(R^(A))₂ (for example, R^(A)'s are each independently a hydrogen atom or an alkyl group (including all of a linear alkyl group, a branched alkyl group, and a cyclic alkyl group)). The number of carbon atoms in the alkyl group is, for example, 1 to 10, preferably 1 to 6, and more preferably 1 to 3. Moreover, the alkyl group may further have a substituent (for example, a group exemplified in the substituent group T).

In view of further improving the dispersibility, X is preferably a hydroxyl group, a carboxylic acid group, a phosphonic acid group, a phosphoric acid group, a phosphinic acid group, a sulfonic acid group, or a thiol group.

In General Formula (I), in a case where a plurality of X's are present, the plurality of X's may be the same as or different from each other.

Y represents an aromatic hydrocarbon ring group or an aromatic heterocyclic group.

The aromatic hydrocarbon ring group may be any one of a monocyclic aromatic hydrocarbon ring group or a polycyclic aromatic hydrocarbon ring group.

A monocyclic aromatic hydrocarbon ring constituting the monocyclic aromatic hydrocarbon ring group is not particularly limited, but is 5-membered to 10-membered ring, for example, and is preferably a 5-membered or 6-membered ring. Examples of the monocyclic aromatic hydrocarbon ring include a cyclopentadienyl ring, a benzene ring, and the like.

The polycyclic aromatic hydrocarbon ring is not particularly limited as long as two or more of the monocyclic aromatic hydrocarbon rings are contained, but is more preferably a fused ring containing two or more benzene rings, and is even more preferably a fused ring containing three or more benzene rings. The upper limit of the number of the monocyclic aromatic hydrocarbon rings contained in the fused ring is not particularly limited, but is, for example, 10 or smaller in many cases.

Specific examples of the polycyclic aromatic hydrocarbon ring include biphenylene, indacene, acenaphthylene, fluorene, phenalene, phenanthrene, anthracene, fluoranthene, acephenanthrylene, aceanthrylene, pyrene, chrysene, tetracene, pleiadene, picene, perylene, pentaphene, pentacene, tetraphenylene, hexaphene, and triphenylene. In view of superior effects of the present invention, among them, the polycyclic aromatic hydrocarbon ring is more preferably a fused ring containing two or more benzene rings, even more preferably a fused ring containing three or more benzene rings, particularly preferably pyrene or perylene, and most preferably pyrene.

The aromatic heterocyclic group may be any one of a monocyclic aromatic heterocyclic group or a polycyclic aromatic heterocyclic group. A polycyclic aromatic heterocyclic ring constituting the polycyclic aromatic heterocyclic group means a fused ring having two or more monocyclic aromatic heterocyclic rings and a fused ring having one or more monocyclic aromatic heterocyclic rings and one or more monocyclic aromatic hydrocarbon rings.

The monocyclic aromatic heterocyclic ring is not particularly limited, but is 5-membered to 10-membered ring, for example, and is preferably a 5-membered or 6-membered ring. Examples of a hetero atom contained in the monocyclic aromatic heterocyclic ring include a nitrogen atom, an oxygen atom, and a sulfur atom.

Examples of the monocyclic aromatic heterocyclic ring include a thiophene ring, a thiazole ring, an imidazole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring.

Specific examples of the polycyclic aromatic heterocyclic ring include a benzimidazole ring, an indole ring, a quinoline ring, a quinoxaline ring, and the like.

In view of further improving the dispersibility, Y is preferably an aromatic hydrocarbon ring group and more preferably a polycyclic aromatic hydrocarbon ring group.

The aromatic hydrocarbon ring group or the aromatic heterocyclic group represented by Y may have a substituent (for example, a group exemplified in the substituent group T).

Z represents an aldehyde group (—CHO), a succinimide group, an onium group, a halogenated alkyl group, a halogen atom (a F atom, a Cl atom, a Br atom, and an I atom), a nitrile group (—CN), a nitro group (—NO₂), an acryloyl group (—COCH₂═CH₂), a methacryloyl group (—COCH(CH₃)═CH₂), an oxetanyl group, a vinyl group (—CH═CH₂), an alkynyl group (a group obtained by removing one hydrogen atom from alkyne, and examples thereof include an ethynyl group and a prop-2-yn-1-yl group), a maleimide group, or a group having a carbonate group (for example, an alkyl carbonate group (—O—CO—O—R^(B): R^(B) will be described later.)).

The succinimide group, the oxetanyl group, and the maleimide group each represent a group formed by removing one hydrogen atom at any position from the compound represented by the following formula.

Furthermore, the onium group means a group having an onium salt structure. The onium salt is a compound which is generated in a case where a compound having an electron pair not being involved in chemical bonding forms a coordinate bond with another cationic compound through the electron pair. Generally, the onium salt contains a cation and an anion.

The onium salt structure is not particularly limited, and examples thereof include an ammonium salt structure, a pyridinium salt structure, an imidazolium salt structure, a pyrrolidinium salt structure, a piperidinium salt structure, a triethylenediamine salt structure, a phosphonium salt structure, a sulfonium salt structure, a thiopyrylium salt structure, and the like. Moreover, the type of the anion used as a counter is not particularly limited, and known anions are used. The valence of the anion is not particularly limited. Examples of the anion include monovalent to trivalent anions, and monovalent and divalent anions are preferable.

As the onium group, a group having an ammonium salt structure represented by General Formula (A1) is particularly preferable.

In General Formula (A1), R^(1A) to R^(3A) each independently represent a hydrogen atom or an alkyl group (including all of a linear alkyl group, a branched alkyl group, and a cyclic alkyl group). The number of carbon atoms in the alkyl group is, for example, 1 to 10, preferably 1 to 6, and more preferably 1 to 3. M⁻ represents an anion. * represents a bonding position. Moreover, the alkyl group may further have a substituent (for example, a group exemplified in the substituent group T).

The halogenated alkyl group is not particularly limited, and examples thereof include a group in which one or more halogen atoms are substituted on an alkyl group having 1 to 10 carbon atoms. The number of carbon atoms in the alkyl group (including all of a linear alkyl group, a branched alkyl group, and a cyclic alkyl group) is preferably 1 to 6 and more preferably 1 to 3. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom, a chlorine atom, or a bromine atom is preferable. Moreover, the halogenated alkyl group may further have a substituent (for example, a group exemplified in the substituent group T).

The group having a carbonate group is not particularly limited as long as the group has a carbonate group, and examples thereof include an alkyl carbonate group (—O—CO—O—R^(B)).

The number of carbon atoms in the alkyl group represented by R^(B) is, for example, 1 to 10, preferably 1 to 6, and more preferably 1 to 3. Moreover, the alkyl group may further have a substituent (for example, a group exemplified in the substituent group T).

In General Formula (I), in a case where a plurality of Z's are present, the plurality of Z's may be the same as or different from each other.

L¹ and L² each independently represent a single bond, any one selected from the group consisting of —O—, —CO—, —S—, —CS—, —NR¹¹—, —N═N—, and a divalent hydrocarbon group, or a divalent linking group obtained by combining two or more selected from the group. The divalent hydrocarbon group may further have a substituent (for example, a group exemplified in the substituent group T).

Examples of the divalent hydrocarbon group include an alkylene group, an alkenylene group (for example, —CH═CH—), an alkynylene group (for example, and an arylene group (for example, a phenylene group). The alkylene group may be linear, branched, or cyclic. Moreover, the number of carbon atoms thereof is preferably 1 to 10, more preferably 1 to 6, and even more preferably 1 to 3.

R¹¹ represents a hydrogen atom or an alkyl group (which may be linear, branched, or cyclic. The number of carbon atoms is preferably 1 to 6 and more preferably 1 to 3).

In view of further improving the dispersibility, as L¹ and L², each independently, a single bond, -AL-, —CO—, —CO—O—, —O—CO—, -AL-O—, —O-AL-, -AL-CO—O—, —CO—O-AL-, -AL-O—CO—, —O—CO-AL, -AL-O-AL-, -AL-NR¹¹—CO—, -AL-CO—NR¹¹—, —NR¹¹—CO-AL-, —CO—NR¹¹-AL-, or -AR-O-AL-O— is preferred, and a single bond is more preferred. AL represents an alkylene group having 1 to 10 carbon atoms (the number of carbon atoms is preferably 1 to 6 and more preferably 1 to 3). Moreover, AR represents an arylene group. The alkylene group and the arylene group may further have a substituent (for example, a group exemplified in the substituent group T).

In General Formula (I), a plurality of L¹'s may be the same as or different from each other. Moreover, a plurality of L²'s may be the same as or different from each other.

The molecular weight of the specific compound is, for example, 100 or greater, and in view of further improving the dispersibility of the surface-modified inorganic nitride, is preferably 150 or greater and more preferably 280 or greater. In view of solubility, the molecular weight thereof is preferably 3,000 or less and more preferably 2,000 or less.

Hereinafter, the specific examples of the specific compound are shown, but the present invention is not limited to the examples. Moreover, in the following examples, “Me” represents a methyl group and “Et” represents an ethyl group.

<Method for Producing Surface-Modified Inorganic Nitride>

The method for producing the surface-modified inorganic nitride is not particularly limited, and examples thereof include a method including a step of bringing an inorganic nitride into contact with a specific compound.

The inorganic nitride and the specific compound are brought into contact with each other, for example, by stirring a solution containing the inorganic nitride and the specific compound.

The type of a solvent of the solution is not particularly limited, but an organic solvent is preferable. Examples of the organic solvent include ethyl acetate, methyl ethyl ketone, dichloromethane, and tetrahydrofuran.

The solution may contain other components such as the polymerizable monomer which will be described later. In this case, the obtained mixture can also be used as the composition which will be described later.

The mixing ratio between the inorganic nitride and the specific compound may be determined in consideration of the structure and surface area of the inorganic nitride and the molecular structure of the molecule of the specific compound such as an aspect ratio.

The stirring conditions (a rotation speed for stirring and a temperature condition) are not particularly limited.

<Surface-Modified Inorganic Nitride>

In the surface-modified inorganic nitride, the specific compound modifies the surface of the inorganic nitride. It is preferable that the specific compound modifies the surface of the inorganic nitride by forming a bond such as a hydrogen bond with the inorganic nitride.

The shape of the surface-modified inorganic nitride is not particularly limited, and the surface-modified inorganic nitride may have a granule shape, a film shape, or a plate shape.

In the surface-modified inorganic nitride, a mass ratio between the specific compound and the inorganic nitride (mass of specific compound/mass of inorganic nitride) is not particularly limited. However, in view of further improving the dispersibility of the surface-modified inorganic nitride, the mass ratio is preferably 0.0001 to 0.5 and more preferably 0.0005 to 0.1.

In the surface-modified inorganic nitride, the specific compound may be adsorbed onto the surface of the inorganic nitride, or another surface modifier may be adsorbed onto the surface of the inorganic nitride. That is, the surface-modified inorganic nitride may contain the inorganic nitride and the specific compound and another surface modifier which are adsorbed onto the surface of the inorganic nitride.

[Composition]

The surface-modified inorganic nitride exhibits improved dispersibility in various materials. By exploiting these characteristics, the surface-modified inorganic nitride can be used as a composition for various uses by being mixed with other materials.

The content of the surface-modified inorganic nitride in the composition is not particularly limited, and according to the use of the composition, optimal content is appropriately selected. The content of the surface-modified inorganic nitride with respect to the total solid content in the composition is 0.01% to 95% by mass, for example, and particularly, in view of allowing the characteristics of the surface-modified inorganic nitride to be more markedly exhibited, the content of the surface-modified inorganic nitride with respect to the total solid content in the composition is preferably 20% to 95% by mass, more preferably 30% to 90% by mass, and even more preferably 40% to 85% by mass.

The composition may contain one kind of surface-modified inorganic nitride or two or more kinds of surface-modified inorganic nitrides.

As described above, the composition may contain materials other than the surface-modified inorganic nitride. Examples of the materials include a polymerizable monomer, a curing agent, a curing accelerator, a polymerization initiator, and the like.

Hereinafter, various components will be specifically described.

<Polymerizable Monomer>

The polymerizable monomer is a compound cured by a predetermined treatment using heat, light, or the like.

The polymerizable monomer has a polymerizable group.

The type of the polymerizable group is not particularly limited, and examples thereof include known polymerizable groups. In view of reactivity, a functional group capable of an addition polymerization reaction is preferable and a polymerizable ethylenic unsaturated group or a ring-opening polymerizable group is more preferable. Examples of the polymerizable group include an acryloyl group, a methacryloyl group, an oxiranyl group, a vinyl group, a maleimide group, a styryl group, an allyl group, an oxetanyl group, and the like. A hydrogen atom in each group may be substituted with another substituent such as a halogen atom. Particularly, in view of reactivity, the polymerizable group is preferably a group selected from the group consisting of an acryloyl group, a methacryloyl group, an oxiranyl group, an oxetanyl group, and a vinyl group.

Furthermore, the number of polymerizable groups contained in the polymerizable monomer is not particularly limited. However, in view of further improving the heat resistance of a cured substance obtained by curing the composition, the number of polymerizable groups is preferably 2 or more and more preferably 3 or more. The upper limit thereof is not particularly limited, but is 8 or smaller in many cases.

The type of the polymerizable monomer is not particularly limited, and known polymerizable monomers can be used. Examples of the polymerizable monomer include the epoxy resin monomer and the acrylic resin monomer described in paragraph “0028” in JP4118691B, the epoxy compound described in paragraphs “0006” to “0011” in JP2008-013759A, the epoxy resin mixture described in paragraphs “0032” to “0100” in JP2013-227451A, and the like.

Furthermore, a bisphenol A diglycidyl ether monomer, a bisphenol F diglycidyl ether monomer, and the like can also be used.

The content of the polymerizable monomer in the composition is not particularly limited, and according to the use of the composition, optimal content is appropriately selected. Particularly, the content of the polymerizable monomer with respect to the total solid content in the composition is preferably 10% to 90% by mass, more preferably 15% to 70% by mass, and even more preferably 15% to 60% by mass.

The composition may contain one kind of polymerizable monomer or two or more kinds of polymerizable monomers.

It is preferable that the polymerizable monomer exhibits liquid crystallinity. That is, the polymerizable monomer is preferably a liquid crystal compound. In other words, the polymerizable monomer is preferably a liquid crystal compound having a polymerizable group.

Furthermore, it is also preferable that a cured substance of the polymerizable monomer exhibits liquid crystallinity. The cured substance of the polymerizable monomer means a cured substance obtained by curing the polymerizable monomer, and does not contain the aforementioned surface-modified inorganic nitride. If necessary, for obtaining the cured substance, the curing agent which will be described later may be used.

As described above, it is preferable that the polymerizable monomer or a cured substance thereof exhibits liquid crystallinity. That is, the polymerizable monomer or a cured substance thereof is preferably a liquid crystal component.

The polymerizable monomer may be any of a rod-like liquid crystal compound or a disk-like liquid crystal compound. That is, the polymerizable monomer may be any of a rod-like liquid crystal compound having a polymerizable group or a disk-like liquid crystal compound having a polymerizable group.

Hereinafter, the rod-like liquid crystal compound and the disk-like liquid crystal compound will be specifically described.

(Rod-Like Liquid Crystal Compound)

Examples of the rod-like liquid crystal compound include azomethines, azoxies, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexane carboxylic acid phenyl esters, cyanophenyl cyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolans, and alkenylcyclohexyl benzonitriles. In addition to these low-molecular-weight liquid crystal compounds described above, high-molecular-weight liquid crystal compounds can also be used. The aforementioned high-molecular-weight liquid crystal compounds are polymer compounds obtained by polymerizing rod-like liquid crystal compounds having a low-molecular-weight reactive group.

Examples of preferable rod-like liquid crystal compounds include a rod-like liquid crystal compound represented by General Formula (XXI).

Q¹L¹¹¹-A¹¹¹L¹¹³-M-L¹¹⁴-A¹¹²-L¹¹²-Q²  General Formula (XXI):

In the formula, Q¹ and Q² are each independently a polymerizable group, and L¹¹¹, L¹¹², L¹¹³, and L¹¹⁴ each independently represent a single bond or a divalent linking group. A¹¹¹ and A¹¹² each independently represent a divalent linking group (spacer group) having 1 to 20 carbon atoms. M represents a mesogenic group.

The definition of the polymerizable group is as described above.

As the divalent linking group represented by L¹¹¹, L¹¹², L¹¹³, or L¹¹⁴, a divalent linking group selected from the group consisting of —O—, —S—, —CO—, —NR¹¹²—, —CO—O—, —O—CO—O—, —CO—NR¹¹²—, —NR¹¹²—CO—, —O—CO—, —CH₂—O—, —O—CH₂—, —O—CO—NR¹¹², NR¹¹²—CO—O—, and —NR¹¹²—CO—NR¹¹²— is preferable. R¹¹² is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom.

A¹¹¹ and A¹¹² each represent a divalent linking group having 1 to 20 carbon atoms. Particularly, A¹¹¹ and A¹¹² preferably each represent an alkylene group having 1 to 12 carbon atoms, an alkenylene group having 1 to 12 carbon atoms, or an alkynylene group having 1 to 12 carbon atoms, and more preferably each represent an alkylene group having 1 to 12 carbon atoms.

The divalent linking group is preferably linear and may contain oxygen atoms or sulfur atoms that are not adjacent to each other. Furthermore, the divalent linking group may have a substituent, and examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, or a bromine atom), a cyano group, a methyl group, and an ethyl group.

Examples of the mesogenic group represented by M include known mesogenic groups. Particularly, a group represented by General Formula (XXII) is preferable.

—(W¹-L¹¹⁵)_(n)-W²—  General Formula (XXII):

In the formula, W¹ and W² each independently represent a divalent cyclic alkylene group, a divalent cyclic alkenylene group, an arylene group, or a divalent heterocyclic group. L¹¹⁵ represents a single bond or a divalent linking group. n represents 1, 2, or 3.

Examples of W¹ and W² include 1,4-cyclohexenediyl, 1,4-cyclohexanediyl, 1,4-phenylene, pyrimidine-2,5-diyl, pyridine-2,5-diyl, 1,3,4-thiadiazole-2,5-diyl, 1,3,4-oxadiazole-2,5-diyl, naphthalene-2,6-diyl, naphthalene-1,5-diyl, thiophene-2,5-diyl, and pyridazine-3,6-diyl. In a case where W¹ and W² each represent 1,4-cyclohexanediyl, the compound may be any of constitutional isomers of a trans-isomer and a cis-isomer, or a mixture in which the isomers are mixed at any ratio. Among them, a trans-isomer is preferable.

Each of W¹ and W² may have a substituent. Examples of the substituent include the groups exemplified in the substituent group T. More specifically, examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom), a cyano group, an alkyl group having 1 to 10 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, and the like), an alkoxy group having 1 to 10 carbon atoms (for example, a methoxy group, an ethoxy group, and the like), an acyl group having 1 to 10 carbon atoms (for example, a formyl group, an acetyl group, and the like), an alkoxycarbonyl group having 1 to 10 carbon atoms (for example, a methoxycarbonyl group, an ethoxycarbonyl group, and the like), an acyloxy group having 1 to 10 carbon atoms (for example, an acetyloxy group, a propionyloxy group, and the like), a nitro group, a trifluoromethyl group, a difluoromethyl group, and the like.

Examples of the divalent linking group represented by L¹¹⁵ include the specific examples of the divalent linking groups represented by L¹¹¹ to L¹¹⁴, such as —CO—O—, —O—CO—, —CH₂—O—, and —O—CH₂—.

Examples of those preferable as the basic skeleton of the mesogenic group represented by General Formula (XXII) will be shown below. These may be substituted with the aforementioned substituent.

The compound represented by General Formula (XXI) can be synthesized with reference to the method described in JP1999-513019A (JP-H11-513019A) (WO97/000600).

The rod-like liquid crystal compound may be a monomer having the mesogenic group described in JP1999-323162A (JP-H11-323162A) and JP4118691 B.

(Disk-Like Liquid Crystal Compound)

The disk-like liquid crystal compound has a disk-like structure in at least a portion thereof. The disk-like structure has at least an aromatic ring. Therefore, the disk-like liquid crystal compound can form a columnar structure by forming a stacking structure based on the intermolecular π-π interaction.

Specific examples of the disk-like structure include the triphenylene structure described in Angew. Chem. Int. Ed. 2012, 51, 7990-7993 or JP1995-306317A (JP-H07-306317A), the trisubstituted benzene structure described in JP2007-002220A or JP2010-244038A, and the like.

Particularly, In a case where the disk-like liquid crystal compound is used as a polymerizable monomer, a thermally conductive material showing high thermally conductive properties is obtained. The reason for this is considered as below. While the rod-like liquid crystal compound can only linearly (one-dimensionally) conduct heat, the disk-like liquid crystal compound can flatwise (two-dimensionally) conduct heat in a normal direction, and accordingly, the number of heat conduction paths increases, and the thermal conductivity is improved.

Furthermore, in a case where the disk-like liquid crystal compound is used, the heat resistance of the cured substance of the composition is improved.

It is preferable that the disk-like liquid crystal compound has three or more polymerizable groups. The cured substance of the composition containing the disk-like liquid crystal compound having three or more polymerizable groups tends to have a high glass transition temperature and high heat resistance. Compared to a rod-like liquid crystal compound, the disk-like liquid crystal compound is more likely to have three or more polymerizable groups without affecting the characteristics of a mesogenic portion. The number of polymerizable groups contained in the disk-like liquid crystal compound is preferably 8 or smaller and more preferably 6 or smaller.

As the disk-like liquid crystal compound, a compound represented by General Formula (XI) or a compound represented by General Formula (XII) is preferable.

In the formula, R¹¹, R¹², R¹³, R¹⁴, R¹⁵, and R¹⁶ each independently represent *—X¹¹-L¹¹-P¹¹ or *—X¹²—Y¹², * represents a position bonded to a triphenylene ring, two or more among R¹¹, R¹², R¹³, R¹⁴, R¹⁵, and R¹⁶ represent *—X¹¹-L¹¹-P¹¹, X¹¹ and X¹² each independently represent a single bond, —O—, —C(═O)—, —OC(═O)—, —OC(═O)O—, —OC(═O)NH—, —OC(═O)S—, —C(═O)O—, —C(═O)NH—, —C(═O)S—, —NHC(═O)—, —NHC(═O)O—, —NHC(═O)NH—, —NHC(═O)S—, —S—, —SC(═O)—, —SC(═O)O—, —SC(═O)NH—, or —SC(═O)S—, L¹¹ represents a divalent linking group or a single bond, P¹¹ represents a polymerizable group, and Y¹² represents a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, or a group obtained by substituting one methylene group or two or more methylene groups in a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms with —O—, —S—, —NH—, —N(CH₃)—, —C(═O)—, —OC(═O)—, or —C(═O)O—.

It is preferable that three or more out of R¹¹, R¹², R¹³, R¹⁴, R¹⁵, and R¹⁶ represent *—X¹¹-L¹¹-P¹¹. Particularly, it is more preferable that any one or more out of R¹¹ or R¹², any one or more out of R¹³ or R¹⁴, and any one or more out of R¹⁵ or R¹⁶ represent *—X¹¹-L¹¹-P¹¹. It is even more preferable that all of R¹¹, R¹², R¹³, R¹⁴, R¹⁵, and R¹⁶ represent *—X¹¹-L¹¹-P¹¹. It is particularly preferable that all of R¹¹, R¹² and R¹⁶ represent the same group represented by *—X¹¹-L¹¹-P¹¹.

X¹¹ and X¹² are each independently preferably —O—, —OC(═O)—, —OC(═O)O—, —OC(═O)NH—, —C(═O)O—, —C(═O)NH—, —NHC(═O)—, or NHC(═O)O—, more preferably —OC(═O)—, —C(═O)O—, —OC(═O)NH—, or —C(═O)NH—, and even more preferably —C(═O)O—.

L¹¹ represents a single bond or a divalent linking group which links X¹¹ and P¹¹ to each other. Examples of the divalent linking group include —O—, —OC(═O)—, —C(═O)O—, an alkylene group having 1 to 10 carbon atoms (preferably having 1 to 8 carbon atoms and more preferably having 1 to 6 carbon atoms), an arylene group having 6 to 20 carbon atoms (preferably having 6 to 14 carbon atoms and more preferably having 6 to 10 carbon atoms), a group obtained by combining these, and the like.

Examples of the alkylene group having 1 to 10 carbon atoms include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, and the like.

Examples of the arylene group having 6 to 20 carbon atoms include a 1,4-phenylene group, a 1,3-phenylene group, a 1,4-naphthylene group, a 1,5-naphthylene group, an anthracenylene group, and the like, and a 1,4-phenylene group is preferable.

Each of the alkylene group and the arylene group may have a substituent. Examples of the substituent include the groups exemplified in the substituent group T. The number of substituents is preferably 1 to 3 and more preferably 1. The substitution position of the substituent is not particularly limited. As the substituent, a halogen atom or an alkyl group having 1 to 3 carbon atoms is preferable and a methyl group is more preferable. It is also preferable that the alkylene group and the arylene group are unsubstituted. It is particularly preferable that the alkylene group is unsubstituted.

P¹¹ represents a polymerizable group. The definition of the polymerizable group is as described above.

P¹¹ is preferably an acryloyl group, a methacryloyl group, or an oxiranyl group.

In a case where P¹¹ is a hydroxy group, L¹¹ includes an arylene group, and it is preferable that the arylene group is bonded to P¹¹.

Y¹² represents a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, or a group obtained by substituting one methylene group or two or more methylene groups in a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms with —O—, —S—, —NH—, —N(CH₃)—, —C(═O)—, —OC(═O)—, or —C(═O)O—.

In a case where Y¹² represents a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms or a group obtained by substituting one methylene group or two or more methylene groups in a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms with —O—, —S—, —NH—, —N(CH₃)—, —C(═O)—, —OC(═O)—, or —C(═O)O—, Y¹² may be substituted with a halogen atom.

Examples of the linear or branched alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a n-pentyl group, an isopentyl group, a neopentyl group, a 1,1-dimethylpropyl group, a n-hexyl group, an isohexyl group, a linear or branched heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, and a dodecyl group.

The number of carbon atoms in the cyclic alkyl group is preferably 3 or more and more preferably 5 or more. The number of carbon atoms in the cyclic alkyl group is preferably 20 or smaller, more preferably 10 or smaller, even more preferably 8 or smaller, and particularly preferably 6 or smaller. Examples of the cyclic alkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group.

Y¹² is preferably a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, or an alkylene oxide group having 1 to 20 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 12 carbon atoms or an ethylene oxide group or propylene oxide group having 1 to 20 carbon atoms.

Regarding specific examples of the compound represented by General Formula (XI), compounds described in paragraphs “0028” to “0036” in JP1995-281028A (JP-H07-281028A), JP1995-306317A (JP-H07-306317A), paragraphs “0016” to “0018” in JP2005-156822A, paragraphs “0067” to “0072” in JP2006-301614A, and Liquid Crystal Handbook (published on 2000 from MARUZEN Co., Ltd.), pp. 330 to 333 can be referred to.

In the formula, A², A³, and A⁴ each independently represent —CH═ or —N═, R¹⁷, R¹⁸, and R¹⁹ each independently represent *—X¹¹—(Z²¹—X²¹²)_(n21)-L²¹-P²¹ or *X²¹¹—(Z²²−X₂₂₂)^(n22)—Y²², * represents a position bonded to a central ring, two or more among R¹⁷, R¹⁸, and R¹⁹ represent *—X¹¹—(Z²¹—X²¹²)_(n21)-L²¹-P²¹, X²¹¹, X²¹², and X²²² each independently represent a single bond, —O—, —C(═O)—, —OC(═O)—, —OC(═O)O—, —OC(═O)NH—, —OC(═O)S—, —C(═O)O—, —C(═O)NH—, —C(═O)S—, —NHC(═O)—, —NHC(═O)O—, —NHC(═O)NH—, —NHC(═O)S—, —S—, —SC(═O)—, —SC(═O)O—, —SC(═O)NH—, or —SC(═O)S—, Z²¹ and Z²² each independently represent an aromatic group as a 5-membered or 6-membered ring or a non-aromatic group as a 5-membered or 6-membered ring, L²¹ represents a divalent linking group or a single bond linking X²¹² and P²¹ to each other, P²¹ represents a polymerizable group, Y²² represents a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, or a group obtained in a case where one methylene group or two or more methylene groups in a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms are substituted with —O—, —S—, —NH—, —N(CH₃)—, —C(═O)—, —OC(═O)—, or —C(═O)O—, n21 and n22 each independently represent an integer of 0 to 3, and in a case where each of n21 and n22 is 2 or greater, a plurality of groups represented by Z²¹—X²¹² and Z²²—X²²² may be the same as or different from each other.

It is preferable that all of R¹⁷, R¹⁸, and R¹⁹ represent *—X²¹¹—(Z²¹—X²¹²)_(n21)-L²¹-P²¹. It is more preferable that all of R¹⁷, R¹⁸, and R¹⁹ represent the same group represented by *—X²¹¹—(Z²¹—X²¹²)_(n21)-L²¹-P²¹.

As X²¹¹, X²¹², and X²²², a single bond or —OC(═O)— is preferable.

Z²¹ and Z²² each independently represent an aromatic group as a 5-membered or 6-membered ring or a non-aromatic group as a 5-membered or 6-membered ring. Examples thereof include a 1,4-phenylene group, a 1,3-phenylene group, a divalent heterocyclic group, and the like.

The aromatic group and the non-aromatic group may have a substituent. Examples of the substituent include the groups exemplified in the substituent group T. The number of substituents is preferably 1 or 2 and more preferably 1. The substitution position of the substituent is not particularly limited. As the substituent, a halogen atom or a methyl group is preferable. As the halogen atom, a chlorine atom or a fluorine atom is preferable. It is also preferable that the aromatic group and the non-aromatic group are unsubstituted.

Examples of the divalent heterocyclic ring include the following heterocyclic rings.

In the formulae, * represents a portion bonded to X²¹¹ and ** represents a portion bonded to X²¹² (or X²²²); A⁴¹ and A⁴² each independently represent a methine group or a nitrogen atom; and X⁴ represents an oxygen atom, a sulfur atom, a methylene group, or an imino group.

It is preferable that at least one of A⁴¹ or A⁴² represents a nitrogen atom. It is more preferable that both of A⁴¹ and A⁴² represent a nitrogen atom. Furthermore, it is preferable that X⁴ represents an oxygen atom.

L²¹ represents a divalent linking group or a single bond linking X²¹² and P²¹ to each other, and has the same definition as L¹¹ in General Formula (XI). As L²¹, —O—, —OC(═O)—, —C(═O)O—, an alkylene group having 1 to 10 carbon atoms (preferably 1 to 8 carbon atoms and more preferably 1 to 6 carbon atoms), or a group obtained by combining these is preferable.

P²¹ represents a polymerizable group. The definition of the polymerizable group is as described above.

P²¹ is preferably an acryloyl group, a methacryloyl group, or an oxiranyl group.

Y²² represents a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, or a group obtained in a case where one methylene group or two or more methylene groups in a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms are substituted with —O—, —S—, —NH—, —N(CH₃)—, —C(═O)—, —OC(═O)—, or —C(═O)O—. Y²² has the same definition as Y¹² in General Formula (XI), and the preferred range thereof is also the same as that of Y¹² in General Formula (XI).

n21 and n22 each independently represent an integer of 0 to 3, preferably represent an integer of 1 to 3, and more preferably represent 2 or 3.

Regarding the details and specific examples of the compound represented by General Formula (XII), the description in paragraphs “0013” to “0077” in JP2010-244038A can be referred to, and the contents thereof are incorporated into the present specification.

In view of reinforcing stacking by reducing electron density and making it easy to form a columnar aggregate, it is preferable that the compound represented by General Formula (XI) or (XII) is a compound having a hydrogen-bonding functional group.

Examples of the hydrogen-bonding functional group include —OC(═O)NH—, —C(═O)NH—, —NHC(═O)—, —NHC(═O)O—, —NHC(═O)NH—, —NHC(═O)S—, SC(═O)NH—, and the like.

Specific examples of compounds particularly preferable as the compound represented by General Formula (XI) and the compound represented by General Formula (XII) include the following compounds.

** represents a bonding position. The same is true for the following description.

The compound represented by General Formula (XI) can be synthesized based on the methods described in JP1995-306317A (JP-H07-306317A), JP1995-281028A (JP-H07-281028A), JP2005-156822A, and JP2006-301614A.

The compound represented by General Formula (XII) can be synthesized based on the methods described in JP2010-244038A, JP2006-076992A, and JP2007-002220A.

<Other Components>

(Curing Agent)

The composition may further contain a curing agent.

The type of the curing agent is not particularly limited, and the curing agent may be a compound which can cure the aforementioned polymerizable monomer. The curing agent is preferably a compound having a functional group selected from the group consisting of a hydroxy group, an amino group, a thiol group, an isocyanate group, a carboxy group, a (meth)acryloyl group, and a carboxylic acid anhydride group, and more preferably a compound having a functional group selected from the group consisting of a hydroxy group, a (meth)acryloyl group, an amino group, and a thiol group.

The curing agent preferably has two or more of the functional groups described above and more preferably has two or three of the functional groups described above.

Examples of the curing agent include an amine-based curing agent, a phenol-based curing agent, a guanidine-based curing agent, an imidazole-based curing agent, a naphthol-based curing agent, an acrylic curing agent, an acid anhydride-based curing agent, an active ester-based curing agent, a benzoxazine-based curing agent, a cyanate ester-based curing agent, and the like. Among these, an acrylic curing agent, a phenol-based curing agent, or an amine-based curing agent is preferable.

The content of the curing agent in the composition is not particularly limited, but is preferably 1% to 50% by mass and more preferably 1% to 30% by mass with respect to the total solid content in the composition.

(Curing Accelerator)

The composition may further contain a curing accelerator.

The type of the curing accelerator is not particularly limited, and examples thereof include triphenylphosphine, 2-ethyl-4-methylimidazole, a boron trifluoride amine complex, 1-benzyl-2-methylimidazole, and those described in paragraph “0052” in JP2012-067225A.

The content of the curing accelerator in the composition is not particularly limited, but is preferably 0.1% to 20% by mass with respect to the total solid content in the composition.

(Polymerization Initiator)

The composition may further contain a polymerization initiator.

Particularly, in a case where the specific compound or the polymerizable monomer has a (meth)acryloyl group, it is preferable that the composition contains the polymerization initiator described in paragraph “0062” in JP2010-125782A and paragraph “0054” in JP2015-052710A.

The content of the polymerization initiator in the composition is not particularly limited, but is preferably 0.1% to 50% by mass with respect to the total solid content in the composition.

(Solvent)

The composition may further contain a solvent.

The type of the solvent is not particularly limited, but the solvent is preferably an organic solvent. Examples of the organic solvent include ethyl acetate, methyl ethyl ketone, dichloromethane, tetrahydrofuran, and the like.

<Method for Producing Composition>

The method for producing the composition is not particularly limited, and known methods can be adopted. For example, the composition can be produced by mixing together the aforementioned various components (the surface-modified inorganic nitride, the polymerizable monomer, and the like) by a known method. At the time of mixing, the various components may be mixed at a time or mixed sequentially.

Furthermore, as described above, at the time of producing the surface-modified inorganic nitride, the inorganic nitride, the specific compound, and other additives may be mixed together at a time so as to produce the composition.

<Method for Curing Composition>

The method for curing the composition is not particularly limited, and an optimal method is appropriately selected according to the type of the polymerizable monomer. The curing method may be a thermal curing reaction or a photocuring reaction for example, and is preferably a thermal curing reaction.

The heating temperature at the time of the thermal curing reaction is not particularly limited, and may be appropriately selected within a range of 50° C. to 200° C., for example. Furthermore, at the time of performing the thermal curing reaction, heating treatment may be performed plural times at different temperatures.

The curing reaction is preferably performed on the composition formed into a sheet. Specifically, for example, coating may be performed using the composition, and the obtained coating film may be subjected to the curing reaction. At this time, press working may also be performed.

The curing reaction may be a semi-curing reaction. That is, the obtained cured substance may be in a so-called B stage state (semi-cured state).

In a case where the cured substance semi-cured as described above is disposed to contact a device or the like, and then permanently cured by heating and the like, the adhesiveness between a layer containing a thermally conductive material, which is the cured substance, and the device is further improved.

<Use>

The surface-modified inorganic nitride and the composition described above can be used for various uses. For example, the surface-modified inorganic nitride and the composition can be applied to various fields as a pigment, a catalyst, an electrode material, a semiconductor material, a thermally conductive material, a lubricant, and the like. That is, a material containing the surface-modified inorganic nitride can be used for various uses. The shape of the material containing the surface-modified inorganic nitride is not particularly limited, and may be a sheet shape, for example.

Particularly, the surface-modified inorganic nitride and the composition described above are preferably used for forming a thermally conductive material or a lubricant.

Hereinafter, the suitable use will be specifically described.

(Thermally Conductive Material)

The thermally conductive material according to the embodiment of the present invention contains the surface-modified inorganic nitride.

The thermally conductive material may contain components other than the surface-modified inorganic nitride, and examples thereof include a binder. Examples of the binder include a binder formed by curing the polymerizable monomer described above.

The thermally conductive material can be prepared by curing the composition described above. That is, the composition can be used for forming the thermally conductive material. Regarding the preparation of the thermally conductive material including a curing reaction, “Highly Thermally Conductive Composite Material” (CMC Publishing CO., LTD., written by Yoshitaka TAKEZAWA) can be referred to.

The thermally conductive material may contain the surface-modified inorganic nitride, and the method for producing the thermally conductive material is not limited to the aspect in which the aforementioned composition is used.

The thermally conductive material is a material having excellent thermally conductive properties, and can be used as a heat dissipation material such as a heat dissipation sheet. For example, the thermally conductive material can be used for dissipating heat from various devices such as power semiconductor devices. More specifically, in a case where a device with a thermally conductive layer is prepared by disposing a thermally conductive layer containing the thermally conductive material on a device, the heat generated from the device can be efficiently dissipated by the thermally conductive layer.

The shape of the thermally conductive material is not particularly limited, and the thermally conductive material can be molded to have various shapes according to the use. Typically, the thermally conductive material is preferably in the form of a sheet.

The thermally conductive material may be in a completely cured state or a semi-cured state (B stage state described above). As described above, in a case where the thermally conductive material is in a semi-cured state, by disposing the thermally conductive material on a device and then performing a heating treatment thereon, a thermally conductive layer having excellent adhesiveness can be formed on the device.

(Lubricant)

The surface-modified inorganic nitride can be suitably used for preparing a lubricant. That is, examples of the use of the surface-modified inorganic nitride include a lubricant containing the surface-modified inorganic nitride.

The lubricant can be prepared by mixing the surface-modified inorganic nitride with grease (a low-molecular-weight monomer or a polymer resin) or the like. As the grease, known materials can be used.

As an example of the inorganic nitride in the surface-modified inorganic nitride at the time of preparing the lubricant, boron nitride is preferable. This is because boron nitride is known to exhibit lubricating properties by itself in a high-temperature region.

EXAMPLES

Hereinafter, the present invention will be more specifically described based on Examples. The materials, the amount and proportion of the materials used, the details of treatments, the procedure of treatments, and the like shown in the following Examples can be appropriately changed within a range that does not depart from the gist of the present invention. Accordingly, the scope of the present invention is not limitedly interpreted by the following Examples.

[Establishment of Experimental System]

Alizarin is a compound which is well known to modify the surface of zinc oxide by being bonded to zinc oxide (JP5479175B). Alizarin (12 mg, produced by Wako Pure Chemical Corporation, catalog No. 015-01151) was dissolved in 300 mL of methyl ethyl ketone. By using a visible absorption spectrum (measurement apparatus: UV-3100PC manufactured by Shimadzu Corporation) of the solution, the absorbance at a wavelength of 427 nm was measured. Furthermore, separately prepared fine zinc oxide particles (produced by Wako Pure Chemical Corporation, 264-00365) were added to the solution (25 mL) and gently stirred. After about 5 minutes, the supernatant solution of the obtained solution was filtered using a 0.45-micron filter (Minisart RC15 manufactured by Sartorius). For the obtained filtrate, the absorbance was measured in the same manner as described above. As a result, the absorbance of the solution obtained after the addition of the fine zinc oxide particles was 27.6% of the absorbance of the solution obtained before the addition of the fine zinc oxide particles. From the obtained result, it was understood that, by comparing the absorbances as described above, from the decrement of the absorbance, it is possible to determine whether or not the surface of an inorganic nitride is modified with a compound and to determine the degree of surface modification.

(Adsorption Test onto Inorganic Nitride)

The following compound C-2 (10 mg) was dissolved in acetonitrile (100 mL), and further diluted to 1/10 to obtain a solution. An ultraviolet⋅visible absorption spectrum (measurement apparatus: UV-3100PC manufactured by Shimadzu Corporation) of the obtained solution was measured, and an absorbance X at an absorption maximum wavelength was determined.

Thereafter, boron nitride “SGPS” (0.5 g) produced by Denka Company Limited was added to the solution (20 mL) and stirred for several seconds. After stirring, the supernatant solution of the obtained solution was filtered using a filter. By using the obtained filtrate, an ultraviolet⋅visible absorption spectrum (measurement apparatus: UV-3100PC manufactured by Shimadzu Corporation) of the filtrate was measured in the same manner as described above, and an absorbance Y at an absorption maximum wavelength was determined. The results of the ultraviolet⋅visible absorption spectra are shown in FIG. 1.

Subsequently, a ratio (residual rate (%)) of the absorbance Y of the filtrate, which was obtained by the addition of boron nitride, measured at an absorption maximum wavelength to the absorbance X of the solution, to which boron nitride was not yet added, measured at an absorption maximum wavelength was calculated. The smaller residual rate (%) means superior adsorption onto boron nitride. The results are shown in Table 1.

In addition, the residual rate (%) of the absorbance after the addition of boron nitride was calculated in the same procedure as that described above by using each compound shown in Table 1, which will be described later, instead of C-2. The results are summarized in Table 1 which will be described later.

Furthermore, the results of the ultraviolet⋅visible absorption spectra in a case where the following compounds were used are respectively shown in FIGS. 2 to 5.

TABLE 1 Absorption Absorbance Absorbance maximum before after Residual wavelength adsorption adsorption rate (nm) (Absorbance X) (Absorbance Y) (%) C-2 288 1.24 1.06 85.5 C-3 318 0.42 0.38 90.5 C-8 412 0.64 0.08 12.5 C-15 418 0.73 0.33 45.2 C-28 418 0.53 0.03 5.7

As is evident from the results in Table 1, in a case where the respective compounds shown in Table 1 were used, a decrease in the absorbance was confirmed in all cases. From this result, it was confirmed that the respective compounds shown in Table 1 were adsorbed onto the surface of the boron nitride. In addition, even in a case where a compound other than the compounds shown in Table 1 was used among compounds C-1 to C16 and C-18 to C-35 used in Examples which will be described later, a decrease in the absorbance was confirmed. From this result, it was confirmed that a compound other than the compounds shown in Table 1, among compounds C-1 to C16 and C-18 to C-35 used in Examples which will be described later, was also adsorbed onto the surface of the boron nitride.

[Preparation and Evaluation of Composition]

<Various Components>

Various components used in Examples and Comparative Examples will be shown below.

(Polymerizable Monomer)

As the polymerizable monomer, compounds represented by the following A-1 to A-8 were used.

A-1: Mixture of bisphenol F diglycidyl ether resin and bisphenol A diglycidyl ether resin, epoxy equivalent: 165.7 g/eq, total chlorine: 0.008% by mass, viscosity: 2,340 mPa·s, produced by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD.

A-5: “TMPT” (trimethylolpropane triacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.)

A-6: “OXT-121” (polyfunctional oxetane, manufactured by TOAGOSEI CO., LTD.)

(Additive)

As the additive, compounds represented by the following B-1 to B-3 were used.

B-3: “KAYAHARD GPH-65” (produced by Nippon Kayaku Co., Ltd.)

(Solvent)

As the solvent, methyl ethyl ketone (MEK) was used.

(Polymerization Initiator)

As the polymerization initiator, VAm-110 (oil-soluble azo polymerization initiator, produced by Wako Pure Chemical Corporation) was used.

(Inorganic Nitride)

As the inorganic nitride, the followings were used.

SGPS (boron nitride, average particle diameter: 12 μm, produced by Denka Company Limited)

S-30 (aluminum nitride, average particle diameter: 35 μm, produced by MARUWA Co., Ltd.)

(Surface Modifier)

As the surface modifier, compounds represented by the following C-1 to C-16 and C-18 to C-35 were used.

(Comparative Surface Modifier)

As the comparative surface modifier, compounds represented by the following D-1 to D-4 were used.

Example 1

Various components shown in Table 2 below were mixed in the order of the polymerizable monomer, the methyl ethyl ketone (MEK), the additive, the surface modifier (compound represented by General Formula (I)), and the polymerization initiator, and then the inorganic nitride was added thereto. The obtained mixture was treated for five minutes with a rotating and revolving mixer (manufactured by THINKY CORPORATION, AWATORI RENTARO ARE-310) to obtain a composition 1. In addition, the final solid content of the composition 1 was adjusted with MEK so as to have the solid content concentration (described in the column of “Solvent”) described in Table 2.

Then, by using an applicator, a release surface of a polyester film (NP-100A, manufactured by PANAC CO., LTD., film thickness: 100 μm) was coated with the composition 1 such that the film thickness thereof became about 600 μm, and the obtained film was left to stand in the air for 1 hour to obtain a coating film 1.

Subsequently, a coating film surface of the coating film 1 was covered with another polyester film, and the coating film was cured by treatment with vacuum heat press (heat plate temperature: 130° C., degree of vacuum: <1 kPa, pressure: 12 MPa, treatment time: 5 minutes) to obtain a resin sheet. The polyester films on both surfaces of the resin sheet were peeled, thereby obtaining a thermally conductive sheet 1 having an average film thickness (in Example 1, the average film thickness was 350 μm) shown in Table 1.

(Evaluations)

The following evaluations were performed with respect to the obtained thermally conductive sheet 1.

[1] Dispersibility Evaluation

The dispersibility was evaluated by using the thermally conductive sheet 1. Specifically, the film thickness of the thermally conductive sheet 1 was measured at any five positions, a standard deviation was determined for variation in the measurement, and the evaluation was performed according to the following standards. A small standard deviation (in other words, small variation in the film thickness) indicates that the surface-modified inorganic nitrides are well dispersed. On the other hand, a large standard deviation (in other words, large variation in the film thickness) means that aggregation or the like occurs in the cured substance and thus surface irregularities are generated, that is, indicates that the dispersibility of the surface-modified inorganic nitride deteriorates.

The film thickness was measured by using “ai-Phase Mobile 1u” manufactured by ai-Phase Co., Ltd.

(Evaluation Standards)

“A”: Standard deviation was less than 5

“B”: Standard deviation was 5 or greater and less than 10

“C”: Standard deviation was 10 or greater and less than 30

“D”: Standard deviation was 30 or greater

The results are shown in Table 2.

[2] Thermally Conductive Properties Evaluation

The thermally conductive properties were evaluated by using the thermally conductive sheet 1. The thermal conductivity was measured by the following method, and the thermally conductive properties were evaluated according to the following standards.

Measurement of thermal conductivity (W/m·K)

(1) By using “ai-Phase Mobile 1u” manufactured by ai-Phase Co., Ltd., thermal diffusivity of the thermally conductive sheet 1 in a thickness direction was measured.

(2) By using a balance “XS204” (“solid specific gravity measuring kit” was used) manufactured by METTLER TOLEDO, the specific gravity of the thermally conductive sheet 1 was measured.

(3) By using “DSC320/6200” manufactured by Seiko Instruments Inc. and software of DSC7, the specific heat of the thermally conductive sheet 1 at 25° C. was determined under the heating condition of 10° C./min.

(4) The obtained thermal diffusivity was multiplied by the specific gravity and the specific heat, thereby calculating the thermal conductivity of the thermally conductive sheet 1.

(Evaluation Standards)

“A”: 15 W/m·K or greater

“B”: 12 W/m·K or greater and less than 15 W/m·K

“C”: 9 W/m·K or greater and less than 12 W/m·K

“D”: Less than 9 W/m·K

The results are shown in Table 2.

Examples 2 to 45 and Comparative Examples 1 to 4

Compositions of Examples and Comparative Examples shown in Table 2 below were obtained in the same procedure as that in Example 1. In addition, the final solid content of each of the compositions was adjusted with MEK so as to have the solid content concentration (described in the column of “Solvent”) described in Table 2.

Furthermore, thermally conductive sheets 2 to 45 and comparative thermally conductive sheets 1 to 4 were prepared from the obtained respective compositions, and were subjected to the same evaluation tests as those in Example 1. The results are shown in Table 2.

In Table 2, the (numerical value) described in the column of each component means a content (% by mass) of each component with respect to the total solid content in the composition.

“Film thickness (μm)” described in Table 2 means an average film thickness of the thermally conductive sheet.

In Table 2, the curing accelerator A used in Example 44 is triphenylphosphine.

TABLE 2 Curable composition Surface modifier Poly- Poly- (compound represented merizable merization Inorganic by General Formula (I)) monomer Additive initiator nitride Type (% by mass) (% by mass) (% by mass) (% by mass) (% by mass) Type of Y Example 1 A-1 (22) B-2 (15) None SGPS (60) C-1 (3) Benzene ring group Example 2 A-1 (22) B-2 (15) None SGPS (60) C-2 (3) Benzene ring group Example 3 A-1 (22) B-2 (15) None SGPS (60) C-3 (3) Naphthalene ring group Example 4 A-1 (22) B-2 (15) None SGPS (60) C-4 (3) Naphthalene ring group Example 5 A-1 (22) B-2 (15) None SGPS (60) C-5 (3) Naphthalene ring group Example 6 A-1 (22) B-2 (15) None SGPS (60) C-6 (3) Phenanthrene ring group Example 7 A-1 (22) B-2 (15) None SGPS (60) C-7 (3) Naphthalene ring group Example 8 A-1 (22) B-2 (15) None SGPS (60) C-8 (3) Pyrene ring group Example 9 A-1 (22) B-2 (15) None SGPS (60) C-9 (3) Pyrene ring group Example 10 A-1 (22) B-2 (15) None SGPS (60)  C-10 (3) Pyrene ring group Example 11 A-1 (22) B-2 (15) None SGPS (60)  C-11 (3) Pyrene ring group Example 12 A-1 (22) B-2 (15) None SGPS (60)  C-12 (3) Pyrene ring group Example 13 A-1 (22) B-2 (15) None SGPS (60)  C-13 (3) Pyrene ring group Example 14 A-1 (22) B-2 (15) None SGPS (60)  C-14 (3) Pyrene ring group Example 15 A-1 (22) B-2 (15) None SGPS (60)  C-15 (3) Pyrene ring group Example 16 A-1 (22) B-2 (15) None SGPS (60)  C-16 (3) Pyrene ring group Curable composition Surface modifier Solvent Evaluation (compound represented (solid content Thermally Film by General Formula (I)) concentration Dispers- conductive thickness Type of X Type of Z (% by mass)) ibility properties [μm] Example 1 Hydroxyl group Aldehyde group MEK (40) B C 350 Example 2 Hydroxyl group Aldehyde group MEK (40) B C 350 Example 3 Hydroxyl group Aldehyde group MEK (40) B C 350 Example 4 Amino group Aldehyde group MEK (40) C C 350 Example 5 Hydroxyl group Aldehyde group MEK (40) B C 350 Example 6 Hydroxyl group Aldehyde group MEK (40) A B 350 Example 7 Phosphoric Aldehyde group MEK (40) B C 350 acid group Example 8 Carboxylic Aldehyde group MEK (40) A A 250 acid group Example 9 Thiol group Aldehyde group MEK (40) A A 250 Example 10 Hydroxyl group Halogen atom MEK (40) A A 250 Example 11 Hydroxyl group Halogen atom MEK (40) A A 250 Example 12 Hydroxyl group Halogen atom MEK (40) A A 250 Example 13 Hydroxyl group Halogen atom MEK (40) A A 250 Example 14 Hydroxyl group Succinimide group MEK (40) A A 250 Example 15 Hydroxyl group Aldehyde group MEK (40) A A 250 Example 16 Hydroxyl group Alkyl MEK (40) A A 250 carbonate group

TABLE 3 Curable composition Surface modifier Polymerizable Polymerization Inorganic (compound represented by General Formula (I)) Table 2 monomer Additive initiator nitride Type (Continued) (% by mass) (% by mass) (% by mass) (% by mass) (% by mass) Type of Y Example 17 A-1 (22) B-2 (15) None SGPS (60) C-18 (3) Pyrene ring group Example 18 A-1 (22) B-2 (15) None SGPS (60) C-19 (3) Pyrene ring group Example 19 A-1 (22) B-2 (15) None SGPS (60) C-20 (3) Pyrene ring group Example 20 A-1 (22) B-2 (15) None SGPS (60) C-21 (3) Pyrene ring group Example 21 A-2 (22) B-2 (15) None SGPS (60) C-15 (3) Pyrene ring group Example 22 A-3 (36) None VAm-110 (1) SGPS (60) C-22 (3) Pyrene ring group Example 23 A-4 (36) None VAm-110 (1) SGPS (60) C-23 (3) Pyrene ring group Example 24 A-3 (36) None VAm-110 (1) SGPS (60) C-24 (3) Pyrene ring group Example 25 A-4 (36) None VAm-110 (1) SGPS (60) C-25 (3) Pyrene ring group Example 26 A-3 (36) None VAm-110 (1) SGPS (60) C-26 (3) Pyrene ring group Example 27 A-1 (22) B-2 (15) None SGPS (60) C-27 (3) Pyrene ring group Example 28 A-1 (22) B-2 (15) None SGPS (60) C-28 (3) Pyrene ring group Example 29 A-1 (22) B-2 (15) None SGPS (60) C-29 (3) Pyrene ring group Example 30 A-1 (22) B-2 (15) None SGPS (60) C-30 (3) Pyrene ring group Example 31 A-1 (20) B-2 (12) None SGPS (65) C-15 (3) Pyrene ring group Example 32 A-1 (18) B-2 (9)  None SGPS (70) C-15 (3) Pyrene ring group Curable composition Surface modifier (compound represented Solvent Evaluation by General Formula (I)) (solid content Thermally Film Table 2 concentration conductive thickness (Continued) Type of X Type of Z (% by mass)) Dispersibility properties [μm] Example 17 Hydroxyl group Halogenated alkyl group MEK (40) A A 250 Example 18 Hydroxyl group Nitrile group MEK (40) A A 250 Example 19 Hydroxyl group Nitro group MEK (40) A A 250 Example 20 Hydroxyl group Oxetanyl group MEK (40) A A 250 Example 21 Hydroxyl group Aldehyde group MEK (40) A A 250 Example 22 Hydroxyl group Vinyl group MEK (40) A A 250 Example 23 Hydroxyl group Alkynyl group MEK (40) A A 250 Example 24 Hydroxyl group Acryloyl group MEK (40) A A 250 Example 25 Hydroxyl group Methacryloyl group MEK (40) A A 250 Example 26 Hydroxyl group Maleimide group MEK (40) A A 250 Example 27 Amino group Aldehyde group MEK (40) B A 250 Example 28 Carboxylic acid group Aldehyde group MEK (40) A A 250 Example 29 Hydroxyl group Halogenated alkyl group MEK (40) A A 250 Example 30 Hydroxyl group Halogenated alkyl group MEK (40) A A 250 Example 31 Hydroxyl group Aldehyde group MEK (40) A A 250 Example 32 Hydroxyl group Aldehyde group MEK (40) A A 250

TABLE 4 Curable composition Surface modifier Polymerizable Polymerization Inorganic (compound represented by General Formula (I)) Table 2 monomer Additive initiator nitride Type (Continued) (% by mass) (% by mass) (% by mass) (% by mass) (% by mass) Type of Y Example 33 A-1 (22) B-2 (15) None S-30 (60) C-15 (3) Pyrene ring group Example 34 A-1 (22) B-2 (15) None SGPS (60) C-31 (3) Pyrene ring group Example 35 A-1 (22) B-2 (15) None SGPS (60) C-32 (3) Naphthalene ring group Example 36 A-1 (22) B-2 (15) None SGPS (60) C-33 (3) Naphthalene ring group Example 37 A-1 (22) B-2 (15) None SGPS (60) C-34 (3) Quinoline ring group Example 38 A-1 (22) B-2 (15) None SOPS (60) C-35 (3) Pyrene ring group Example 39 A-1 (22) B-2 (15) None SGPS (60) C-24 (3) Pyrene ring group Example 40 A-5 (36) None VAm-110 (1) SGPS (60) C-24 (3) Pyrene ring group Example 41 A-6 (22) B-3 (15) None SGPS (60) C-24 (3) Pyrene ring group Example 42 A-7 (36) None VAm-110 (1) SGPS (60) C-24 (3) Pyrene ring group Example 43 A-8 (36) None VAm-110 (1) SGPS (60) C-24 (3) Pyrene ring group Example 44 A-1 (36) B-3 (15) Curing SGPS (60) C-35 (3) Pyrene ring group accelerator A (1) Example 45 A-4 (30) B-1 (6)  VAm-110 (1) SGPS (60) C-23 (3) Pyrene ring group Comparative A-1 (22) B-2 (15) None SGPS (60) D-1 (3) Benzene ring group Example 1 Comparative A-1 (22) B-2 (15) None SGPS (60) D-2 (3) Benzene ring group Example 2 Comparative A-1 (22) B-2 (15) None SGPS (60) D-3 (3) Biphenyl group Example 3 Comparative A-1 (22) B-2 (15) None SGPS (60) D-4 (3) Biphenyl group Example 4 Curable composition Surface modifier (compound represented Solvent Evaluation by General Formula (I)) (solid content Thermally Film Table 2 concentration conductive thickness (Continued) Type of X Type of Z (% by mass)) Dispersibility properties [μm] Example 33 Hydroxyl group Aldehyde group MEK (40) B A 350 Example 34 Sulfonic acid group Aldehyde group MEK (40) A A 250 Example 35 Phosphonic acid group Aldehyde group MEK (40) B C 350 Example 36 Phosphinic acid group Aldehyde group MEK (40) B C 350 Example 37 Hydroxyl group Halogen atom MEK (40) C C 350 Example 38 Hydroxyl group Aldehyde group MEK (40) A A 250 Example 39 Hydroxyl group Acryloyl group MEK (40) A A 250 Example 40 Hydroxyl group Acryloyl group MEK (40) A A 250 Example 41 Hydroxyl group Acryloyl group MEK (40) A A 250 Example 42 Hydroxyl group Acryloyl group MEK (40) A A 250 Example 43 Hydroxyl group Acryloyl group MEK (40) A B 250 Example 44 Hydroxyl group Aldehyde group MEK (40) A A 250 Example 45 Hydroxyl group Alkynyl group MEK (40) A A 250 Comparative — Halogen atom MEK (40) D D 350 Example 1 Comparative — Thioisocyanate group MEK (40) D D 400 Example 2 Comparative Carboxylic acid group — MEK (40) D D 350 Example 3 Comparative Hydroxyl group — MEK (40) D D 350 Example 4

As shown in the above tables, it was confirmed that in a case where the surface-modified inorganic nitride according to the embodiment of the present invention is used, the thermal conductivity is further improved. The improvement of thermal conductivity results from the improvement of the dispersibility of the surface-modified inorganic nitride in the sample. That is, it was confirmed that the affinity between the surface-modified inorganic nitride and an organic substance is improved.

Furthermore, through the comparison between Example 15 and Example 33, it was confirmed that in a case where boron nitride is used as the inorganic nitride, the dispersibility is further improved.

Through the comparison among Examples 1 to 45, it was confirmed that in a case where the compound has a hydroxyl group, a carboxylic acid group, a phosphonic acid group, a phosphoric acid group, a phosphinic acid group, a sulfonic acid group, or a thiol group as X in General Formula (I), the compound tends to have further improved dispersibility.

Through the comparison among Examples 1 to 45, it was confirmed that in a case where Y in General Formula (I) is a polycyclic aromatic hydrocarbon ring group containing three or more benzene rings (preferably, a case where Y is a pyrene ring group), the thermally conductive properties are further improved.

Through the comparison among Examples 39 to 43, it was confirmed that in a case where the polymerizable monomer has a group selected from the group consisting of an acryloyl group, a methacryloyl group, an oxiranyl group, an oxetanyl group, and a vinyl group, the thermally conductive properties are further improved. 

What is claimed is:
 1. A surface-modified inorganic nitride comprising: an inorganic nitride; and a compound which is represented by General Formula (I) and is adsorbed onto a surface of the inorganic nitride,

in General Formula (I), X represents a hydroxyl group, a carboxylic acid group, a phosphonic acid group, a phosphoric acid group, a phosphinic acid group, a sulfonic acid group, a thiol group, or an amino group; Y represents an aromatic hydrocarbon ring group or an aromatic heterocyclic group; Z represents an aldehyde group, a succinimide group, an onium group, a halogenated alkyl group, a halogen atom, a nitrile group, an acryloyl group, a methacryloyl group, an oxetanyl group, a vinyl group, an alkynyl group, a maleimide group, or a group having a carbonate group; L¹ and L² each independently represent a single bond, any one selected from the group consisting of —O—, —CO—, —S—, —CS—, —NR¹¹—, —N═N—, and a divalent hydrocarbon group, or a divalent linking group obtained by combining two or more selected from the group; R¹¹ represents a hydrogen atom or an alkyl group; and m and n each independently represent an integer of 1 or greater, and in General Formula (I), in a case where a plurality of X's are present, the plurality of X's may be the same as or different from each other; in a case where a plurality of Z's are present, the plurality of Z's may be the same as or different from each other; in a case where a plurality of L¹'s are present, the plurality of L¹'s may be the same as or different from each other; in a case where a plurality of L²'s are present, the plurality of L²'s may be the same as or different from each other; and in a case where X represents an amino group, Z represents a group other than a halogen atom.
 2. The surface-modified inorganic nitride according to claim 1, wherein X is a hydroxyl group, a carboxylic acid group, a phosphonic acid group, a phosphoric acid group, a phosphinic acid group, a sulfonic acid group, or a thiol group.
 3. The surface-modified inorganic nitride according to claim 1, wherein Y is an aromatic hydrocarbon ring group.
 4. The surface-modified inorganic nitride according to claim 3, wherein Y is a polycyclic aromatic hydrocarbon ring group containing three or more benzene rings.
 5. The surface-modified inorganic nitride according to claim 4, wherein Y is a pyrene ring group.
 6. The surface-modified inorganic nitride according to claim 1, wherein the inorganic nitride is at least one kind of nitride selected from the group consisting of boron nitride and aluminum nitride.
 7. The surface-modified inorganic nitride according to claim 6, wherein the inorganic nitride is boron nitride.
 8. A composition comprising: the surface-modified inorganic nitride according to claim 1; and a polymerizable monomer.
 9. The composition according to claim 8, wherein the polymerizable monomer has a group selected from the group consisting of an acryloyl group, a methacryloyl group, an oxiranyl group, an oxetanyl group, and a vinyl group.
 10. The composition according to claim 8, wherein the polymerizable monomer or a cured substance thereof exhibits liquid crystallinity.
 11. The composition according to claim 8 that is used for forming a thermally conductive material.
 12. A thermally conductive material comprising the surface-modified inorganic nitride according to claim
 1. 13. The thermally conductive material according to claim 12 that is in the form of a sheet.
 14. The thermally conductive material according to claim 12 that is used in a heat dissipation sheet.
 15. A device with a thermally conductive layer, comprising: a device; and a thermally conductive layer which is disposed on the device and contains the thermally conductive material according to claim
 12. 16. The surface-modified inorganic nitride according to claim 2, wherein Y is an aromatic hydrocarbon ring group.
 17. The surface-modified inorganic nitride according to claim 2, wherein the inorganic nitride is at least one kind of nitride selected from the group consisting of boron nitride and aluminum nitride.
 18. The surface-modified inorganic nitride according to claim 3, wherein the inorganic nitride is at least one kind of nitride selected from the group consisting of boron nitride and aluminum nitride.
 19. The surface-modified inorganic nitride according to claim 4, wherein the inorganic nitride is at least one kind of nitride selected from the group consisting of boron nitride and aluminum nitride.
 20. The surface-modified inorganic nitride according to claim 5, wherein the inorganic nitride is at least one kind of nitride selected from the group consisting of boron nitride and aluminum nitride. 